DESCRIPTION (Adapted from Applicant s Description): In 1986, the National Institute of Child Health and Human Development created two multicenter perinatal research networks, the Neonatal Research Network and the Maternal Fetal Medicine Units (MFMU) Network, each consisting of a number of major academic clinical centers, a data coordinating center, and the Institute, itself. The purpose of both Networks was to conduct clinical research aimed at reducing the risk of adverse pregnancy and infant outcome with the ultimate purpose of contributing to the body of well-conducted studies on which to base medical decisions in obstetrics and neonatology. At present, the MFMU Network is planning, conducting and analyzing multiple randomized clinical trials and observational studies in various aspects of perinatal medicine such as preterm birth prevention, preterm labor suppression, prevention of preeclampsia, and the effects of drugs in pregnancy. The George Washington University Biostatistics Center has been the Data Coordinating Center for both Networks since its inception. This applicant continues to serve as such for the MFMU Network. The purpose is to provide expertise and support in study design, study conduct and statistical analysis. The investigators will provide statistical leadership in the design of the study, prepare interim analyses, and perform final analyses in an expeditious and timely manner. They will prepare study documents, including protocols, manuals of operations and case report forms, and will continue to provide a comprehensive data processing system including distributed and central data entry, data base management and data quality control. They will assist investigators in preparation of manuscripts and abstracts from study results and will archive the data for public access. They will also provide administrative support such as: arrangement of logistical services for provision of study drugs and laboratory assays, coordination of meetings, training sessions and outcome reviews. They will manage resources effectively, so that they can start new studies in a timely manner. In summary, they will participate as full members of the Network, with the common goal of understanding and improving the course of pregnancy and neonatal outcome